Means for eliminating disturbances at the ends of submarine telegraph cables



Oct. 1, 1929. w, ESTAUGH 4 1,730,198

MEANS FOR BLIIINATING DISTURBANCES AT THE ENDS OF sUBuARINE TELEGRAPH CABLES Filed Jan. 1 25 nrrm/vm Patented Oct. 1, 1929 UNITED STATES PATENT OFFICE WILLIAM ESTAUGH, OF WANSTEAD, ENGLAND MEANS FOR ELIMINATING DISTURBANCES AT THE ENDS OF SUBMARINE TELEGRAPH CABLES Application filed January 8, 1925, Serial No. 1,286, and in Great Britain October 17, 1924.

This invention relates to submarine telegraphy and has for its object improvements whereby the cable is protected at its ends from earth and other extraneous disturbances.

These improvements consist in surrounding the signalling conductor of a cable for a suitable distance seawards from its land ends. with a conducting screen that is insulated throughout its length connected to the earth at one point only on the earth side of the transmitting or receiving instrument.

As is well-known earth currents and other electric disturbances act inductively on the signalling conductor of cables as heretofore constructed and in carrying out the present invention an insulated conducting screen is interposed between it and the earth to intercept the lines of force set up by any extraneous disturbance so as to effectually protect the signalling conductor. Any charge or potential induced in this protecting screen is immediately discharged to earth Where it Will tend to neutralize the disturbance or its cause. In this way the etliciency of the screen is also maintained.

According to one mode of carrying my invention into practice the cable which is pro vided with an insulated signalling conductor of known construction is surrounded at its land end for such a distance seawards as may be judged to be necessary in each case with an outer conductor insulated from it and the surrounding earth except at one point where it is provided with means of conducting away charges induced in it. This means may consist of a connection with the earthed terminal of the receiving instrument when the cable is worked simplex or to the earthed terminal of the transmitter when working duplex.

The insulated conducting screen may be formed of helically applied tape, suitably stranded wires or otherwise.

The usual external sheathing is employed to provide the necessary mechanical protection.

I will now proceed to more particularly describe the present invention with the aid of the accompanying drawings in which- Fig. 1 is a diagram showing one end of a cable constructed according to the present invention connected to apparatus arranged for duplex working and Fig. 2 is a similar diagram showing the improved cable connected to apparatus arranged for simplex working.

According to the construction shown in the drawings the cable consists of a signalling conductor a surrounded by insulation 7). At the land ends, the said insulated conductor is surrounded for such a distance seawards as may be found necessary in each case, by a hollow conductor 0 which is in turn surrounded by insulation (Z through which any extraneous disturbances act inductively on the hollow conductor 0 which thus screens the inner signalling conductor (0.

According to the arrangement shown in Fig. 1 the hollow conductor 0 is connected to the earthed terminal 6 of the transmitter f through which the induced charges are led to earth. The other terminal 9 of the transmitter is connected to the signalling conductor a of the cable and the artificial cable 7a through branches 2', and the block sending condensers is, Z. The receiver or is connected to the bridge circuit 72 in the usual way.

According to the arrangement shown in Fig. 2 the hollow conductor 0 is connected to the earthed terminal 6 of the receiver m. 5

I claim:

1. A submarine electric signalling cable having an insulated signalling conductor surrounded at either or both of its land ends by a hollow insulated conductor each of which is connected to the earth at one point substantially as set forth.

2. A submarine electric signalling cable having an insulated signalling conductor surrounded ateither or both of its land ends by a hollow insulated conductor connected to the earth at its shoreward end substantially as set forth.

3. A submarine electric signalling cable having an insulated signalling conductor, a hollow insulated conductor that surrounds said signalling conductor at either or both of its land ends, said hollow conductor being connected to the earth side of the local trans.

Initting or receiving instrument substantially as set forth.

4. A submarine electric signalling cable having an insulated signaling conductor, a hollow insulated conductor that surrounds said signalling conductor at either or both of its land ends, said hollow conductor being connected to the earth through the outer sheathing of the cable substantially'as set forth.

In testimony whereof, I have signed my name to this specification at 61 and 62, Chancery Lane, in the county of London, England, this 17th day of December, 1924:.

WILLIAM ESTAUGH. 

